IN-SITU ASSESSMENT OF CELL-PROLIFERATION AT THE INVASIVE FRONT OF ORAL SQUAMOUS-CELL CARCINOMAS

In oral squamous cell carcinoma (OSCC) the histopathological malignanc y grading of the invasive front has been found to offer the most relia ble prognostic parameter. In the present study we compared such tumour front grading of 100 OSCCs with the in situ growth fraction demonstra ted by MIB1 immunostaining following wet autoclave antigen retrieval. MIB1 labelling indices (LIs) were estimated both at the invasive front and in the central parts of OSCCs using two different evaluation meth ods (overall and random counting) to investigate whether MIB1 LIs repr esent a possible biological background for the tumour front grading. S tatistically highly significantly increased MIB1 LIs were found at the invasive tumour fronts with both counting methods compared with the c entres of the same tumours. For LI estimation the classic overall coun ting procedure proved to be superior. However, in contrast to tumour f ront grading, MIB1 LIs revealed no correlation with the clinical outco me of the patients concerned. Our results demonstrate that the invasiv e tumour front of an OSCC is composed of (a) tumour subpopulation(s) w ith higher proliferative activity. However, determination of the proli ferative activity by MIB1 of this tumour area offers no prognostic inf ormation.